The builder seams to try to access to a file
'/myapp/backend/feed/list' that does not exist.
The point is that /backend/ folder is my server backend, only
containing serverside scripts. "Feed/list" is a controller...
If I search in my code, I obviously found this:

(in file /myapp/models/feed.js)

[...]

/**

*
Find all Feed

*/

findAll
: "GET /megalopolis/backend/feed/list",

/**

*
Find one Feed

*/

findOne
: "GET /megalopolis/backend/feed/{id}",

[...]

Which is the server call to perform when trying to list the Feed
objects...